Several bugs in CSP.py, patch included
GoogleCodeExporter opened this issue · comments
Reproduce:
$ python
>>> from csp import *
>>> backtracking_search(australia, mcv=True, fc=True)
-> Results in wrong coloring
Several issues:
- Forward checking and Arc Consistency are severely broken. The most severe
issue is in line 86, where information about pruned domains from previous
steps is wrongly discarded.
- Most constrained variable-heuristic has it backwards and orders the least
constrained variable first
- Least constraining value-heuristic fails to compile on modern python
- The map of USA is wrong (New York adjacent to California), some borders
missing
The included patch fixes the described issues plus adds
- The map of France by Regions
- Formulation of the Sudoku-Problem
- Some trivial testing code
Otherwise great book!
Original issue reported on code.google.com by edgar.ho...@gmail.com
on 6 Jul 2009 at 12:17
Attachments:
I confirm these bugs (cost me some hair before I noticed them, having assumed
the
code is correct) and Edgar's fixes work
Original comment by eliben
on 25 Jul 2009 at 7:46
Thanks for the fixes, Edgar, and sorry for the hair-loss. I'll incorporate
these
soon. My dilemma: we're working on a 3rd edition of the text, and some code
will be
different; I don't have time to write the text and maintain two versions of the
code.
But I'll have to come up with some solution soon...
Original comment by peter.no...@gmail.com
on 5 Aug 2009 at 7:19
This issue was closed by revision r81.
Original comment by wit...@gmail.com
on 3 Oct 2011 at 11:02
- Changed state: Fixed